Vertical accumulating conveyor systems have been previously developed. One such conveyor system is described in U.S. Pat. No. 6,568,525, entitled Vertical Conveyor Assembly With Accumulating Pallets that issued to Stone et al. on May 27, 2003. U.S. Pat. No. 6,568,525 is hereby incorporated in its entirety. The conveyor systems includes an endless chain arranged in a horizontal configuration and engages a pair of sprockets positioned at either end of the conveyor system. The endless chain is configured to transport a plurality of pallets along a pair or guide rails. Each pallet includes a clutch sprocket assembly that enables the pallets to be stopped at dedicated stop stations or while contacting other pallets without having to stop the entire conveyor system. Thus, while the drive chain is continually driven, one or more pallets may be stopped and accumulated for loading or unloading while other pallets continue to be moved along the conveyor system.
The vertical type conveyor system is capable of carrying long or wide parts in a more upright position, which minimizes the overall footprint of the conveyor system. Because the parts are carried in an upright position, the attitude of the part never changes, and thus, no special means for holding a part on the pallets is typically required. The configuration of the vertical type conveyor system also enables parts to be continuously recirculated if not removed from the conveyor.
Vertical conveyor systems are typically employed to transport parts between workstations positioned around a perimeter of the conveyor system. In order to perform a manufacturing operation on a part, the part is first removed from the conveyor system. Upon completion of the manufacturing operation, the part is reloaded onto the conveyor system to be transported to the next workstation or to an unloading station. The process of unloading the part from the conveyor system prior to performing an operation on the part adds additional time and cost to the manufacturing process. It is thus desirable to provide a process whereby a manufacturing operation is performed on a part without having to first remove the part from the conveyor system.